Lighting Audit Guide

8/8/2019 Lighting Audit Guide

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LIGHTINGLIGHTINGLIGHTINGLIGHTING AUDITAUDITAUDITAUDIT GUIDEGUIDEGUIDEGUIDE

FOR TEACHERSFOR TEACHERSFOR TEACHERSFOR TEACHERS & STUDENTS& STUDENTS& STUDENTS& STUDENTS

By Clare Pries

April 2008

Coolmob trading as Environment Centre Northern Territory, April 2008


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LIGHTING AUDITLIGHTING AUDITLIGHTING AUDITLIGHTING AUDIT

With lighting accounting for 15 to 25% of the energy consumed at your school any energy

efficiency measures in this area will provide very good opportunities for savings. There are twoprimary reasons why more energy is consumed by lighting at schools than necessary. The firststems from the common perception that it is more economical to leave fluorescent lighting (the

type of lights mainly used in schools) on than to turn on and off as needed. The second is thatin the past lighting systems were designed to use older less efficient lamps and fittings, anddue to the low costs of energy, over-lighting was common practice. This section deals with

these issues, identifies how energy savings can be made, and provides the information requiredto effectively under-take a lighting audit at your school.

TURN OFF LIGHTS!TURN OFF LIGHTS!TURN OFF LIGHTS!TURN OFF LIGHTS!

One reason why people believe it is more economical to leave fluorescent lights on is becausethe initial inrush of current to start lights is considerably higher than when they are operating,

this is true, however, it is only for a very short time (much less than a second). The totalenergy used during the inrush current is equivalent to only a few seconds of normal operation.The other reason used to justify leaving these lights on is the effect that switching lights on andoff has on the life-span of the lamps. Again the belief is correct, lamp-life is reduced with

switching, however, as the lamp is not required to operate for as long each day the amount oftime (in years) before the lamp needs to be replaced is longer and the amount of energy usedis less. The economics of the impact of switching is complicated and depends on the type offittings, and, the cost of lamps, labour, disposal and electricity. The results of an analysis takingall these factors into consideration for the use of fluorescent lamps in the average NorthernTerritory school, show, that it is economical to turn fluorescent lights off when leaving a roomfor around 10-15 minutes.1

TOTOTOTOO MUCH LIGHT!O MUCH LIGHT!O MUCH LIGHT!O MUCH LIGHT!

New fluorescent tube lamps produce around 20% more light than older fluorescents, and have

better colour rendering (good colour rendering make objects appear more natural and bright)

2

.The provision in the past to over-light and the installation of new lamps as your older lamps fail

are the primary factors that lead to unnecessary energy consumption by existing lightingsystems. If your fluorescent lighting system is over 15yrs old it is likely that it is consumingmore energy than it needs to. A very efficient fluorescent lighting system for classrooms has anenergy consumption of 6 8 Watts per square metre, older less efficient systems can have an

energy consumption of up to 30+ Watts per square metre.

TOO LITTLE LIGHT!TOO LITTLE LIGHT!TOO LITTLE LIGHT!TOO LITTLE LIGHT!

It is possible that your lighting system has a very high energy use per square metre and onlyprovide the light needed. The causative factors for this generally involve the following:

Old less efficient lamps still being used. Lamp reflective fittings and diffusers not being cleaned regularly. Light output from dirty

fixtures can be reduced by as much as 35% 3. Light fixtures should be cleaned at leastonce every year.

Dark coloured or dusty classroom surfaces The reflectance of wall surfaces plays animportant part in your lighting design, up to 40% losses can result if wall surfaces arenot regularly cleaned14.

The accumulative losses of all these factors can result in lighting levels 70% lower than couldbe achieved with your current lighting system.

1The analysis has been based on a function developed by A. Carriere and M. Rae, published in: Economics of Switching Fluorescent Lamps, IEEETransaction on Industry Applications, Vol. 24, No. 3, May/June 1988.2Sustainable Energy Development Office Government of Western Australia, Technology Table 1, Section 5.1 Lighting in Commercial Buildings

and Offices, Energy Saving Manual Energy Smart Toolbox, http://energysmart.com.au/sedotoolbox/index.asp3Platts Research & Consulting, 2004, Boosting Lighting Efficiency with Reflectors and Maintenance and Light Output Declines With Time,available athttp://www.bchydro.com/business/investigate/investigate6014.html


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IS YOUR LIGHTING SYSTEM EFFICIENT?IS YOUR LIGHTING SYSTEM EFFICIENT?IS YOUR LIGHTING SYSTEM EFFICIENT?IS YOUR LIGHTING SYSTEM EFFICIENT?

The first step in determining the efficiency of your fluorescent lighting system, is to calculate

the energy used per square metre. This is achieved by dividing the classroom floor area by thetotal wattage of the lighting system. The second step is to measure the lighting lux levels. A luxis the lumens per square metre and a lumen is the measurement for light. Australian Standards

are produced which recommend the minimum light lux levels required to provide theappropriate lighting requirements for a task. The following table lists the recommended luxlevels for selected areas in a school.

Source: AS1680.2.3 (Interior lighting, Part 2.3: Educational and training facilities)

Type of interior or activity Illuminance

lux

Classrooms: General use classrooms 240

Laboratories, Music Rooms 320

Libraries: Audio listening areas 160

Audio visual areas, Book Stacks 240

Circulation & Amenity Areas:

Toilets, change rooms, locker rooms, cleaners rooms

80

Corridors, passage ways, ramps 40

Stairs Internal: 80 External: 20

Entrance halls, lobbies, foyers, waiting rooms 160

Enquiry desks 320Administration areas: General tasks involving typing, reading, writing 320

Background/environment 160

Meeting rooms 320

Training rooms, seminar rooms 240

Photocopying Intermittent: 160

Sustained: 240

First Aid Centres Rest rooms: 40

Treatment rooms: 400

Cafeterias/ Kitchens General: 160

Counters, food preparation,cooking, washing up: 240

Indoor Sports Facilities Recreation & training: 300

Competition: 500

HOW TO MEASURE LUX LEVELS OF A ROOMHOW TO MEASURE LUX LEVELS OF A ROOMHOW TO MEASURE LUX LEVELS OF A ROOMHOW TO MEASURE LUX LEVELS OF A ROOMAn instrument designed to measure light levels is called a lux meter. These can be purchased(the cost of these devices can vary from $50 to $350), hired from instrument hire businesses orshould be available to loan from the Infrastructure Sustainability Unit.

Where to take measurements: At 5 or 6 different locations in the room being measured.

At desk height for classrooms and offices, and at the floorlevel for general passage ways such as corridors.

When to take measurements: The amount of light a room receives from its windows will

vary at different times of the day and year. Lux readingsshould be taken when day lighting is at a minimum, that is,early in the morning or late in the afternoon depending on the

location of windows, or, on an overcast day.

How to take measurements: The meters are simple to use and read. Simply place the sensor where you wish to take

measurement allow to settle then take note of reading. Lux readings can vary by asmuch as 30-40 Lux within a distance of only a few centimetres, so it is good practice totake a couple of measurements in the same general position and note the lowest figure.

Movement of people near the sensor will affect the reading so try to minimize movementat time of reading. Standing between light sources and sensor will lower Lux readings.

Examples of lux meters


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CALCULATE THE EFFICIENCY OF YOUR LIGHTING SYSTEMSCALCULATE THE EFFICIENCY OF YOUR LIGHTING SYSTEMSCALCULATE THE EFFICIENCY OF YOUR LIGHTING SYSTEMSCALCULATE THE EFFICIENCY OF YOUR LIGHTING SYSTEMS

Use a copy of the floor plans available for your school on PDF from the InfrastructureSustainability Unit, or, use a tape measure to physically measure each room being assessed.

Floor plans will have the scale used, noted at the bottom. The area for area 3 & 4 in theexample above would have a total floor area of 12.5mtrs x 9mtrs = 112.5m2.

Note the number of lamps in each fixture and the number of fixtures within the room. Find outwhat type of lamps are used.

The most common type of lamp used for school classrooms and office buildings isthe T8 linear fluorescent tube. These lamps have a diameter of 26mm and comein 600mm/18W, 1200mm/36W, and 1500mm/58W. Older lighting systems maystill use less efficient 38mm T12 tubes which come in 600mm/20W,1200mm/40W, 1500mm/64W. Very new systems may have 16mm T5 tubes

installed, these come in 550mm/14W, 1150mm/28W, and 1450mm/35W.

For other lamp types you will need to check with your maintenance staff on the type and wattage as most

can not be determined through a visual inspection alone.

You will also need to check with maintenance staff what type of ballasts4 are used for your fluorescentlights (electronic or magnetic).

The table below gives estimates on the total wattage of common lamp/ballast systems usedwithin a school.

4For an excellent description of how fluorescent lamps work and what ballasts do check out http://home.howstuffworks.com/fluorescent-lamp.htm/printable.

5m

5m

2.5

m

5m

4m

T5 (top), T8 (bottom)


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LAMPLAMPLAMPLAMP BALLASTBALLASTBALLASTBALLAST WATTSWATTSWATTSWATTS

Classrooms & OfficesClassrooms & OfficesClassrooms & OfficesClassrooms & Offices

Magnetic 2418W - 600mm T8 Linear Fluorescent

Electronic 21

Magnetic 4336W - 1200mm T8 Linear Fluorescent

Electronic 38

20W - 600mm T12 Linear Fluorescent Magnetic 26

40W - 1200mm T12 Linear Fluorescent Magnetic 47

14W - 550mm T5 Linear Fluorescent Electronic 18

28W - 1150mm T5 Linear Fluorescent Electronic 32

Magnetic 43

36W - 410mm Single U-Tube

Electronic 38

Laboratories, Passage ways & ToiletsLaboratories, Passage ways & ToiletsLaboratories, Passage ways & ToiletsLaboratories, Passage ways & Toilets

Magnetic 35

28W 210mm Square CompactFluorescent

Electronic 31

125W Mercury Vapour5

140

Gym / AssemblyGym / AssemblyGym / AssemblyGym / Assembly

High -Bay

400W Metal Halide16

440

Flood light

150W Halogen150

To calculate the Watts/m2 divide the total Watts used by the lighting system by the total floorarea.

Example:

No oflamps

(A)

No offixtures in

room(B)

Type of lamp Total Wattsper lamp

(C)

Total Watts(D)

Total floorarea

(E)

TotalWatts/m2

(D/E)

2/Fixture 24 36W - T8(magnetic)

43 2064(AxBxC)

112.5m2 18.3 W/m2

5To estimate the power used by other sized Mercury Vapour or Metal Halide lamps multiply the lamp watts by 110%.


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HOW YOU CAN INCREASE THE ENERGY EFFICIENCY OF YOUR LIGHTING SYSTEMHOW YOU CAN INCREASE THE ENERGY EFFICIENCY OF YOUR LIGHTING SYSTEMHOW YOU CAN INCREASE THE ENERGY EFFICIENCY OF YOUR LIGHTING SYSTEMHOW YOU CAN INCREASE THE ENERGY EFFICIENCY OF YOUR LIGHTING SYSTEM

OPTIONS AOPTIONS AOPTIONS AOPTIONS A ---- REDUCE TIME LIGHTS ARE TURNED OREDUCE TIME LIGHTS ARE TURNED OREDUCE TIME LIGHTS ARE TURNED OREDUCE TIME LIGHTS ARE TURNED ONNNN

MANUALLY TURN OFF LIGHTS IF LEAVING A ROOM FOR MORE THAN 10-15 MINUTES. $$$$

Use awareness raising campaigns on the costs and myths of leaving lights on when not needed,use student light monitors to check lights are turned off at recess & lunch, get teachers to turnoff lights when they leave rather than leaving for cleaners to turn off, use posters on exit doorsor near light switches to remind people to turn off lights.Note: Lights produce heat which must be removed by the air-conditioning system.Less light power used = less heat = less air-conditioning costs

USE SENSORS, PUSH BUTTON OR DIALUP TIMERS ON LIGHT SWITCHES TOTURN LIGHTS OFF AUTOMATICALLY IN

ROOMS USED INTERMITTENTLY (toilets,staff/meeting rooms, withdrawal rooms).$$$$$$$$

Contact the Infrastructure Sustainability Unit to discuss which type would be suitable for yourschool.

USE LIGHT SENSITIVE PHOTO ACTIVATION SWITCHES ON SECURITY LIGHTS TOENSURE ONLY ON WHEN NEEDED. $$$$$$$$

IDENTIFY LIGHT SWITCHES WITH LABELS This will ensure only thoselights needed will be turned on. $$$$

INSTALL LIGHT SENSITIVE PHOTOACTIVATION SWITCHES TO LIGHTINGCIRCUITS NEAR WINDOWS. $$$$$$$$$$$$

A photocell sensor detects the levels of natural

light and turns lights off or down when sufficient

day-lighting is available. This option will

generally involve re-wiring of circuits and

replacement of existing control gear.

Source: Advanced Building technologies & properties,(Lighting and Daylighting, www.advancedbuildings.org)


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USE TASK LIGHTS FOR TEACHERS DURING AFTER CLASS HOURS $$$$ ---- $$$$$$$$The type of lamps best used will depend on whether it is likely if teachers work stations are

moved from one year to the next. Ceiling or wall mounted lights will have higher costs and arefixed. A trial could be undertaken to assess if desk lamps are suitable. Remember 1 lamp using100W will use a lot less energy than a classroom of 40W lamps, select a lamp with sufficient

light output.

DAY LIGHTING $$$$Use natural light wherever possible. Posters on windows reduce light levels in rooms, findalternative areas to display posters if possible.

OPTIONS BOPTIONS BOPTIONS BOPTIONS B ---- REDUCE THE TOTAL ENERGY USED IN EXISTING LIGHT FIXTURESREDUCE THE TOTAL ENERGY USED IN EXISTING LIGHT FIXTURESREDUCE THE TOTAL ENERGY USED IN EXISTING LIGHT FIXTURESREDUCE THE TOTAL ENERGY USED IN EXISTING LIGHT FIXTURES

REMOVE A LAMP FROM TWIN FIXTURES WHERE LIGHT LUX LEVELS ARE AT LEAST TWICE THERECOMMENDED LEVEL AND FROM TRIPLE FIXTURES WHERE LIGHT LUX LEVELS ARE AT LEAST50% HIGHER THAN RECOMMENDED LEVEL. $$$$ ---- $$$$$$$$

Note: The remaining lamp in a twin fixture may need to be

repositioned to centre of fixture by an electrician. When removinglamps, remove starter and use a sticker stating that lamp shouldnot be replaced. (Stickers can be obtained from the Infrastructure

Sustainability Unit).

Starter

INSTALL LAMP REFLECTORS WHERE LIGHT FIXTURES HAVE POOR REFLECTIVE QUALITIES. $$$$$$$$

Reflectors can be retrofitted to existing fluorescent tubes to increase the amount of lightdirected downward from the fitting. These can be used to reduce the need to increase lightingenergy consumption where light levels are too low, or, to reduce energy consumption through

de-lamping where room lighting levels are at least 80% higher than standards prior to lampremoval and reflector fitting.

An example of a inefficient lighting fixture. Some of the light is being absorbed by the dark

surfaces and some is being diffused into the ceiling cavity.

INSTALL A VOLTAGE REDUCTION DEVICE. $$$$$$$$

After start-up the voltage supply to fluorescent lights can be reduced with only a small effect

on light output (~10-15%), the subsequent lower current produces savings of around 30% inenergy consumption. Voltage reduction control should be considered where light lux levels areat least 40% higher than that recommended by the AustralianStandards. Voltage reduction isonly suitable for lighting systems controlled by magnetic ballasts.


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OPTIONS COPTIONS COPTIONS COPTIONS C ---- USE MORE ENERGY EFFICIENT LAMPS AND FITTINGSUSE MORE ENERGY EFFICIENT LAMPS AND FITTINGSUSE MORE ENERGY EFFICIENT LAMPS AND FITTINGSUSE MORE ENERGY EFFICIENT LAMPS AND FITTINGS

REPLACE OLD T8 HALOPHOSHUR FLUORESCENT TUBES WITH NEW TRIPHOSPHUR T8FLUORESCENT LAMPS. $$$$

Triphosphor lamps use less mercury and have 15-20% greater light output for the same energyuse as older lamps. As the triphosphor are 15-20% brighter, in theory you can remove 15-

20% of the lamps and achieve the same light levels for 15-20% less energy and emissions.

REPLACE T8 FLUORESCENT TUBES WITH PROPRIETARY BRAND, T5 ADAPTORS AND LAMPS, ORLIGHT EMITTING DIODES (LEDS). $$$$$$$$ ---- $$$$$$$$$$$$

These lamps will produce the same amount of light but require less power to operate.

T5 fluorescent lamps are 23% more efficient than T8 Triphosphor and 38%more efficient than T8 standard fluorescent lamps18, requiring less energy to

produce the same amount of light output. T5 lamps normally require a newfitting and an electronic ballast to operate and are therefore most economicalwhen installing new light fixtures. An alternative to fixture replacement is the

use of proprietary brand T5 adaptors which can be installed into the existingfittings providing equivalent light output with reduced energy input.

New to the market LEDs can replace existing fluorescent

lamps maintaining light levels whilst reducing lighting energyconsumption by around 70%. The lamps contain no mercury,have a lifecycle of 50,000-100,000hrs (fluorescent lampshave a lamp life of around 16,000hrs), produce negligibleheat, and do not need ballasts or starters to operate. LEDsare relatively expensive compared to fluorescent lampshowever they have shorter pay-back periods if installed into

lighting fixtures that operate for at least 2700 hours per year. LEDs should be considered forsecurity lighting at your school.

The supply of energy efficient light fittings is developing rapidly, when looking to purchase T5

adaptors or LEDs check with the Infrastructure Sustainability Unit for the latest improvementsin this technology.

REPLACE STANDARD INCANDESCENT GLOBES WITH COMPACT FLUORESCENT GLOBES. $$$$

20Watt Compact Fluorescent 100W Standard Incandescent15W 75W12W 60W9W 40W

(When purchasing compact fluorescent globes be sure to check the colour temperature of thelamp. Values of 4500K and above will provide a bright bluish day-light coloured light, values ofaround 2700K will provide a warm yellowish coloured light.)

REPLACE EXISTING LIGHT FIXTURES WITH NEW HIGH OUTPUT LIGHT FIXTURES. $$$$$$$$$$$$

Fixtures are now available that have almost double the light output to a standard fixture,reducing the number of lamps required to service a given area.


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INSTALL ELECTRONIC OR LOW LOSS MAGNETIC BALLASTS. $$$$$$$$$$$$

Ballasts are a type of transformer and are required to regulate the current going to afluorescent lamp. The cheapest and least efficient type of ballast is standard magnetic. Thoughthese can no longer be manufactured or imported into Australia, most older lighting systems

will still have these installed. Low-loss magnetic ballasts are now available which use 15% to45% less energy than a standard magnetic ballast (2-4W saving per lamp) 6. Electronic ballastsare the most efficient ballast available, eliminate flicker, and reduce the amount of powerdrawn by lamps by around 10%.7

REPLACE MERCURY VAPOUR LAMPS WITH METAL HALIDE OR SODIUM LAMPS. $$$$$$$$$$$$

For indoor lighting applications use metal halide lamps, these lamps provide almost double thelight output for the same energy input as mercury vapour and have good colour rendering. For

outdoor applications, such as car park and security lighting where colour rendering is not asimportant use high or low pressure sodium lamps. High pressure sodium lamps have similarefficiency to metal halides and low pressure around three times more efficient than mercuryvapour. The low pressure sodium lamps have a very distinctive yellow glow.

Example: a 125W mercury vapour lamp could be replaced with a 70W metal halide or high

pressure sodium, or a 40-50W low pressure sodium. The ballasts/control gear for these lampsdiffer and need to be replaced as well.

REPLACE OLD STYLE EXIT LIGHTS WITH NEW LED EXIT LIGHTS. $$$$$$$$$$$$

The economy style exit lights used for most schools inDarwin consume around 10W. New LED exit lamps(as shown in the photos on the left) will consumeonly around 2-3W.

6Based on maximum corrected input power Energy Efficiency Index classifications B1 & B2 stated in Australian MEPS for Fluorescent Ballasts.7Sustainable Energy Development Office Government of Western Australia, Technology Table 1, Section 5.1 Lighting in Commercial Buildings

and Offices, Energy Saving Manual Energy Smart Toolbox, http://energysmart.com.au/sedotoolbox/index.asp


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STEP 1 COLLECT INFORMATION

FIND OUT WHAT TYPE AND HOW MANY LIGHTS ARE USED IN YOUR

SCHOOL

MEASURE OR USE FLOOR PLANS TO CALCULATE FLOOR AREA

SURVEY STAFF/TEACHERS AND ROOMS TO FIND OUT HOW LIGHTS

ARE USED AND IF OPERATIONAL TIMES CAN BE REDUCED

STEP 2 CALCULATE THE ENERGY EFFICIENCY

USE THE INFORMATION FROM STEP 1 TO

DETERMINE THE WATTS PER SQUARE

METRE FOR EACH ROOM

HIGH WATTS/m2> 12W/m2

LOW WATTS/m2< 12W/m2

USE OPTIONS C

TO INCREASE

ENERGY

EFFICIENCY OF

LIGHTING

SYSTEM

MEASURE LUX LEVELS

LOOK AT OPTIONS A FOR OPPORTUNITIES TOREDUCE TIME LIGHTS ARE LEFT ON

AVERAGE LUX READINGS < 40% ABOVE STANDARDS

Old halo-phosphor lamps, dirty fixtures and room surfaces, dark wall colours, and

inefficient reflections from fittings could be reducing the amount of light available.Replace lamps with tri-phosphor tubes, clean classroom and light fixtures, and ifnecessary/possible lighten room surfaces, then re-measure lux levels.

AVERAGE LUX READINGS > 40% ABOVE STANDARDS

Option B recommendations can be considered.

Note on de-lamping: Factors such as glare, colour rendering, and uniformity ofillumination (absence of shadows), all impact on the quality of light, therefore anaggressive de-lamping strategy should be undertaken with care. A de-lamping trialof a single room with sufficiently high light levels should provide a good indicationof the impact on occupants and visual quality. If de-lamping will require the

installation of reflectors and/or the repositioning of lamps in fixtures, advice shouldbe obtained from a lighting specialist or the Infrastructure Sustainability Unit. Inaddition, an operations & maintenance plan should be established which includesgroup lamp replacement and regular cleaning of lamp fixtures and room surfaces tomaximize efficiency and maintain savings.

LUX

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Lighting Audit Guide